A wide variety of identification cards have become a common feature of our society; they include drivers licenses, credit cards, student identification cards, membership identification cards for clubs and other organizations, and numerous others. The base stock for the identification card may be paper; thin sheets of various resins may also be employed. The identification material may be applied to the card by printing, typewriting, handwriting (signatures) or any combination of methods. A small photograph is often included in the composite identification card. Strips of magnetizable material bearing magnetic indicia are also in common use.
Many of these identification cards are protected by heat sealed transparent resin covers. The most common type of covering material is a film of a hard, tough, abrasion-resistant bi-axially oriented polyester; the most frequently used material of this kind is a polyethylene terephthalate film available under the commercial designation Mylar. The inner surface of the polyester film has a coating of polyethylene or other material constituting an adhesive activatable by heat and pressure. To form a protective sealed cover for an identification card, the card is placed between two sheets of this composite film, with the polyethylene coatings facing each other and facing the document itself. The resulting "sandwich" is subjected to heat and pressure to fuse the cover films to the document and to each other. The result is an encapsulated identification card that can withstand long wear and substantial abuse.
Unfortunately, normal wear and even abusive use are not the only possible vicissitudes to which an identification card may be subject. Thus, an identification card coming into the possession of someone other than the rightful owner may be subject to a more sophisticated attack for the purpose of changing a signature, substituting a new photograph, or other alteration. Although the sealed, laminated structure conventionally used, as described above, provided substantial resistance to an attack of this nature, a skillful person can remove a part of the cover film and substitute a critical portion of the identification card, subsequently re-sealing the protective cover over the substitution in a manner that will pass any but the most painstaking of inspections.